CALCAREOUS ALGAE OF THE MIDDLE EAST 93 



clearness of water. However Edelstein (1964) records Dasycladus vermicularis 

 (Scop.) Krasser in the eastern Mediterranean from 18-90 m., represented by well- 

 grown individuals larger than those in the littoral flora ; it seems clear that inferences 

 as to exact water-depths should not be drawn from fossil dasyclads alone. The 

 sheltered parts of coastal bays and some lagoons are favoured habitats, and they are 

 tolerant of the reduced salinities which may occur there. Probably, like most non- 

 stenohaline marine organisms, they are euryhaline and have a limited tolerance for 

 temporary conditions of increased salinity. Such general conditions are associated 

 geologically with regions of uplift, and the fossil dasyclad record confirms this. As 

 with most marine organisms they have a scattered distribution outside the optimum 

 habitat, and Chapman (1961 : 104, 106) gives records of Neomeris on mangrove roots 

 and a stunted population of Batophora in an exposed situation. 



Konishi & Epis (1962) gave a distribution-map showing clearly the restriction of 

 living Neomeris spp. to areas within the marine isocrymes for 20 °C, and a table giving 

 bathymetric occurrences. They discussed the implications of this evidence for the 

 fossil occurrences, concluding that the fossil species probably occupied similar warm- 

 water environments, then more widely-spread, as is generally accepted (e.g. Davis & 

 Elliott 1957 : 269). 



So far as can be deduced from associated fossils and the nature of the rock, the 

 extinct dasyclad floras of the Middle East (and elsewhere) favoured exactly similar 

 environments in the past to those now favoured by their descendants. However, at 

 times of maximum abundance, dissociated debris of calcareous dasyclad origin forms 

 a conspicuous element in sediments deposited further out to sea, for which the term 

 " debris-facies " was introduced (Elliott 1958a). 



In the Permian succession of northern Iraq the dasyclad Mizzia velebitana is 

 abundant at many horizons through most of a thickness of over 800 m. It is 

 accompanied throughout by profuse remains of Gymnocodium bellerophontis and 

 various species of Permocalculus. These Gymnocodiaceae have been variously 

 interpreted (Pia 1937 ; Elliott 1955a ; Konishi 1961) as Codiaceae (Chlorophyceae) 

 or Chaetangiaceae (Rhodophyceae) ; whatever the taxonomic position, both the 

 families cited are quiet-water marine algae today as compared with the reef-forming 

 melobesioids. It is significant that amongst all the Iraq Permian algae there occurs 

 only one solenoporoid, a group supposedly ancestral to the melobesioids (Elliott 

 1965a) and similarly of reef and shoal facies, and that uncommonly ; Solenopora 

 centurionis Pia. The Mizzia-Gymnocodium association, sporadically abundant in the 

 lower or Zinnar Formation, disappears within the lowest beds of the median Satina 

 Evaporite, along with other algae and almost all fossils, but reappears in the upper- 

 most beds, and so into and through the Upper or Darari Formation. At the top this 

 latter shows signs of transition to the overlying but unconformable Lower Triassic, 

 which is in the Werfenian alpine facies without remains of algae. 



The Iraqi Permian contains some beds with a predominantly coral, brachiopod or 

 crinoid fauna (Hudson 1958 ; Dunnington, Wetzel & Morton 1959). Moreover, in 

 some of the algal beds the coarse colander-pore Mizzia- segments are worn, indicating 

 post-mortem drifting from the position of growth. But the algal beds are suffi- 



